W24×335 Steel Beam
A W24×335 is a wide flange steel beam 27.5 inches deep with 13.5-inch flanges, weighing 335 pounds per foot. In ASTM A992 steel (Fy = 50 ksi) it has a design bending strength of 3,825 kip-ft (LRFD) when its compression flange is braced, and a design shear strength of 1,139 kips.
Design a W24×335 beam Opens a 42 ft span in the free beam designer.
W24×335 dimensions
| Dimension | Value |
|---|---|
| Depth, d | 27.5 in |
| Flange width, bf | 13.5 in |
| Flange thickness, tf | 2.48 in |
| Web thickness, tw | 1.38 in |
| Distance to web toe of fillet, kdes | 2.98 in |
| Distance between flange centroids, ho | 25.02 in |
| Cross-sectional area, A | 98.4 in2 |
| Weight | 335 lb/ft |
Dimensions are AISC design values. Detailing dimensions are rounded to the nearest 1/16 in.
W24×335 section properties
| Property | Strong axis (x) | Weak axis (y) |
|---|---|---|
| Moment of inertia, I | 11900 in4 | 1030 in4 |
| Elastic section modulus, S | 864 in3 | 152 in3 |
| Plastic section modulus, Z | 1020 in3 | 238 in3 |
| Radius of gyration, r | 11.0 in | 3.23 in |
| Torsion and slenderness | Value |
|---|---|
| Torsional constant, J | 152 in4 |
| Warping constant, Cw | 161000 in6 |
| Effective radius of gyration, rts | 3.86 in |
| Flange slenderness, bf/2tf | 2.73 |
| Web slenderness, h/tw | 15.6 |
W24×335 bending and shear strength
For ASTM A992 steel (Fy = 50 ksi, E = 29,000 ksi) per AISC 360-16. Its flanges and web are compact for bending, so with its compression flange braced it reaches its full plastic moment.
| Strength | LRFD | ASD |
|---|---|---|
| Bending, compression flange braced | φMn = 3,825 kip-ft | Mn/Ω = 2,545 kip-ft |
| Shear | φVn = 1,139 kips | Vn/Ω = 759 kips |
If the compression flange isn't braced, the beam can buckle sideways before it yields. Up to Lp = 11.4 ft between braces it keeps its full strength; past Lr = 63.1 ft it buckles elastically. With uniform moment between braces (Cb = 1.0):
| Unbraced length, Lb | φMn (LRFD) | Mn/Ω (ASD) |
|---|---|---|
| Braced | 3,825 kip-ft | 2,545 kip-ft |
| 10 ft | 3,825 kip-ft | 2,545 kip-ft |
| 11.4 ft (Lp) | 3,825 kip-ft | 2,545 kip-ft |
| 20 ft | 3,566 kip-ft | 2,373 kip-ft |
| 30 ft | 3,265 kip-ft | 2,172 kip-ft |
| 40 ft | 2,964 kip-ft | 1,972 kip-ft |
| 50 ft | 2,662 kip-ft | 1,771 kip-ft |
| 60 ft | 2,361 kip-ft | 1,571 kip-ft |
| 63.1 ft (Lr) | 2,268 kip-ft | 1,509 kip-ft |
| 70 ft | 2,034 kip-ft | 1,354 kip-ft |
| 80 ft | 1,772 kip-ft | 1,179 kip-ft |
| 90 ft | 1,571 kip-ft | 1,045 kip-ft |
| 100 ft | 1,411 kip-ft | 938 kip-ft |
| 110 ft | 1,280 kip-ft | 852 kip-ft |
A beam with a uniform load between braces has Cb above 1.0 (1.14 for a simple span braced only at its ends), so these values are conservative. The beam designer works out Cb for every segment between braces.
W24×335 load table by span
The largest uniform load a simply supported W24×335 can carry, in kips per foot, with its compression flange braced along its length (by a floor or roof deck, for example). The loads include the beam's own weight of 0.335 kips per foot.
| Span | Factored load (LRFD) | Allowable load (ASD) | Load at span/360 | Load at span/240 |
|---|---|---|---|---|
| 14 ft | 156.1 | 103.9 | 186.3 | 279.5 |
| 16 ft | 119.5 | 79.5 | 124.8 | 187.2 |
| 18 ft | 94.4 | 62.8 | 87.7 | 131.5 |
| 20 ft | 76.5 | 50.9 | 63.9 | 95.9 |
| 22 ft | 63.2 | 42.1 | 48.0 | 72.0 |
| 24 ft | 53.1 | 35.3 | 37.0 | 55.5 |
| 26 ft | 45.3 | 30.1 | 29.1 | 43.6 |
| 28 ft | 39.0 | 26.0 | 23.3 | 34.9 |
| 30 ft | 34.0 | 22.6 | 18.9 | 28.4 |
| 32 ft | 29.9 | 19.9 | 15.6 | 23.4 |
| 34 ft | 26.5 | 17.6 | 13.0 | 19.5 |
| 36 ft | 23.6 | 15.7 | 11.0 | 16.4 |
| 38 ft | 21.2 | 14.1 | 9.32 | 14.0 |
| 40 ft | 19.1 | 12.7 | 7.99 | 12.0 |
| 42 ft | 17.3 | 11.5 | 6.90 | 10.4 |
| 44 ft | 15.8 | 10.5 | 6.00 | 9.00 |
| 46 ft | 14.5 | 9.62 | 5.25 | 7.88 |
| 48 ft | 13.3 | 8.84 | 4.62 | 6.93 |
| 50 ft | 12.2 | 8.14 | 4.09 | 6.14 |
| 52 ft | 11.3 | 7.53 | 3.64 | 5.45 |
| 54 ft | 10.5 | 6.98 | 3.25 | 4.87 |
| 56 ft | 9.76 | 6.49 | 2.91 | 4.37 |
| 58 ft | 9.10 | 6.05 | 2.62 | 3.93 |
| 60 ft | 8.50 | 5.66 | 2.37 | 3.55 |
| 62 ft | 7.96 | 5.30 | 2.15 | 3.22 |
| 64 ft | 7.47 | 4.97 | 1.95 | 2.93 |
| 66 ft | 7.02 | 4.67 | 1.78 | 2.67 |
| 68 ft | 6.62 | 4.40 | 1.63 | 2.44 |
- Factored and allowable loads are limited by bending, or by shear where marked *.
- The deflection columns are the service loads that make the beam sag span/360 or span/240. Compare span/360 with the live load alone and span/240 with dead plus live load, the usual floor limits in IBC Table 1604.3.
Reading the table
At a 42 ft span, a W24×335 carries a factored load of 17.3 kips per foot (LRFD) or an allowable load of 11.5 kips per foot (ASD). A live load of 6.90 kips per foot would deflect it span/360, which is 1.40 in. The beam works if the factored load is under the first number and the live and total loads are under the deflection numbers. For other spans, supports or loads, open it in the beam designer, or follow the steel beam design guide to check one by hand.
W24×335 questions
What does W24×335 mean?
W means a wide flange shape. 24 is its nominal depth in inches (the actual depth is 27.5 in) and 335 is its weight in pounds per foot.
How much does a W24×335 weigh?
335 pounds per foot, so a 20 ft W24×335 weighs about 6,700 pounds.
How far can a W24×335 span?
It depends on the load. Braced along its length, it carries 156.1 kips per foot of factored load at 14 ft and 6.62 kips per foot at 68 ft; the load table has the spans in between. Floor beams are often 41 to 55 ft for this depth (span-to-depth ratios of about 18 to 24), where deflection usually governs.
Is a W24×335 a compact section?
Yes. Its flanges (bf/2tf = 2.73) and web (h/tw = 15.6) are both compact for bending in 50 ksi steel.